How to make tidal wave friendship bracelet?

I haven’t been able to find a guide online or on Youtube on how to make a tidal wave friendship bracelet – it looks really cool, so if any of you can teach me, or post a link to a site that could help me, would be greatly appreciated! (:

this is what it looks like: https://www.etsy.com/listing/26185556/purple-tidal-wave-knotted-friendship